Shell Oil plans to buy smaller British rival Enterprise Oil in a deal worth £4.3 billion sterling.
Shell has agreed a takeover bid of 725p per share for London-based Enterprise, an exploration firm operating in the North Sea, Norway and the Gulf of Mexico.
The bid values Enterprise at £3.5 billion, and Shell said it will also take on debts of around £800 million.
Enterprise shareholders will also be entitled to receive and retain the final dividend of 5.35p per share declared on February 5th.
Mr Walter van de Vijver, a member of the committee of managing directors of the Shell Group of companies, said: "This is an attractive deal that offers a strong complementary fit for Shell EP in the UK North Sea and supports Shell's commitment to Norwegian growth.
"Elsewhere, it provides us with an attractive growth opportunity in Italy and improves Shell's position in Brazil".
Enterprise chairman Sir Graham Hearne said the deal accelerates the delivery of shareholder returns.